An organometal halide perovskite photocathode integrated with a MoS₂catalyst for efficient and stable photoelectrochemical water splitting

Photoelectrochemical water splitting using organometal halide perovskites (OHPs) is an attractive and sustainable method for converting solar energy to hydrogen (H₂). However, the poor stability of OHPs in aqueous electrolytes and the use of Pt, a noble metal, as a hydrogen evolution reaction (HER) catalyst restrict the practical application of OHP-based photocathodes. Herein, we report an efficient and stable OHP-based photocathode using Ti foil as the protective encapsulation layer and earth-abundant and cost-effective MoS₂as the HER catalyst. The fabricated MoS₂/Ti foil/OHP photocathode presents a remarkable half-cell solar-to-hydrogen conversion efficiency of 11.07%, a photocurrent density of −20.6 mA cm⁻²at 0 Vversusthe reversible hydrogen electrode (vs.RHE), and an onset potential of 1.02 Vvs.RHE. Furthermore, the MoS₂/Ti foil/OHP photocathode exhibits a record long-term PEC stability in aqueous electrolytes over 120 h of illumination. Our study provides insights into designing the structure of OHP-based photocathodes for efficient and stable solar H₂production.